Fastener driving tool



0, 1966 H. c. LINGLE ETAL 3,269,274

FASTENER DRIVING TOOL Filed Sept. 8, 1964 an S 9v Q A TT'OR/VEYS.

United States Patent 3,269,274 FASTENER DRIVING TOOL Harrison C. Lingle, Wilmette, and Frank C. Howard,

Wheeling, Ill., assignors to Signode Corporation, a corporation of Delaware Filed Sept. 8, 1964, Ser. No. 394,820 4 Claims. (Cl. 91-417) This invention relates to a fastener driving tool and, particularly, to one that is operated by pneumatic pressure.

Pneumatic-ally operated fastening tools are used in a number of industries, such as automobile, furniture, and construction. These tools have been used to drive various kinds of fasteners, such as staples, tacks, and T-nails through readily pierce able materials. The fasteners in question are generally assembled in strip form and stored in a magazine secured to the tool.

It is, of course, desirable that the tool be as .compact as possible commensurate with the required speed of operation while using minimum quantities of high-pressure air. The tool should be simple in construction, but sufficiently rugged, so that it will have a long life. However, if replacement of the various moving parts is necessary, the design and construct-ion thereof should permit ready access thereto.

In accordance with the present invention, there is provided a compact, rugged, fast acting pneumatic fastener driving tool. The novel tool is made up of a minimum number of internal parts that are readily accessible by removing a cap member. The tool is fired by pulling a trigger that controls the operation of a valve assemblage located immediately adjacent (the cylinder in which the driving piston and attached driver blade are located. The valve assemblage includes a main valve, the movement of which is controlled by a trigger-operated pilot valve. When the main valve is opened by pulling the trigger, air under pressure in the reservoir formed in the handle .of the tool is adm-ittted to the cylinder above the driving piston to quickly and positively drive a fastener into position.

The valve assemblage further includes an exhaust valve that is associated with the main valve. The exhaust valve is designed to be closed when the main valve is open to prevent the leakage of air flowing between the reservoir and cylinder. When the trigger is released, and the main valve closes, the exhaust valve opens to vent the air above the driving piston to permit the piston to be returned to the driving position. The driving piston and blade are returned to the driving position by the highpressure air in the reservoir acting on an unbalanced piston area exposed on the underside .of the piston.

Other advantages of the novel tool design will be seen from the following description and attached drawings, in which:

FIGURE 1 is a crosssectional view of a fastener .driving tool incorporating the present invention; and

FIGURE 2 is an enlarged partial view showing the upper portion of the main valve and associated exhaust valve.

Referringfirst to EIGUR'E jlpthere is illustrated a driving tool 1 having a housing 2 which includes a body por- -tion 3 that also serves as a handle by which the operator '9 that extends through a nose assembly 11 where it con- 3,269,274 Patented August 30, 1966 tacts a fastener to drive it into position. The fastener to be driven, for example, may be the end staple of an adhered row of such fasteners located in a magazine 13 secured to the housing 1.

The fiow of compressed air between the storage chamber 4 and the interior of cylinder 7 above piston 8, hereinafter referred to as chamber 10, is controlled by a main valve assembly 14. The valve assembly 14 is located immediately adjacent cylinder 7 and extends generally parallel thereto. The valve 14 includes a valve head 15 which controls the flow through an opening 16 in gasket 17 of smaller diameter than head 15. The gasket 17 extends across the upper open end of the housing 2 and includes a second transversely spaced opening 18 of a slightly smaller diameter than cylinder 7 with the result that gasket 17 serves as a seat for the piston 8 when in the upward or driving position. The gasket 17 is clamped between a cap 19, plate 20, and the open upper end of tool housing 2. The cap is secured to the housing 2 by a suitable fastening means (not shown).

The cap 19 is recessed to form a chamber 21 that interconnects the reservoir 4 and cylinder chamber 10 above piston 8. When the main valve is opened, the highpressure air introduced into chamber 10 acts on piston 8 to move it and driver 9 with a sharp, quick driving action against the fastener located in the nose assembly 11.

The main valve 1.4- includes a vertically extending stem 24- that extends parallel to the cylinder 7. Connected to the bottom of the stem and extending outwardly therefrom is a piston portion 25 that is slidably disposed in a recess 26 formed by an upwardly extend-ing annular flange 27. The piston 25 and recess 26 define a chamber 28, the function of which will be described hereinafter. The upper surface area of the piston portion 25 exposed to the compressed air in reservoir 4 is larger in area than the similarly exposed undersurface of valve head 15. While the aforementioned diiferential area relationship would result in the main valve 14 being normally maintained in the open position, the valve is maintained closed until the tool is to be operated by introducing air from the reservoir to the chamber 28 beneath the piston 25. It can be appreciated that with this arrangement, the unbalanced forces on the valve 14 act to maintain it closed. The compressed air is introduced into chamber 28 through port 3.0 in stem 24 and longitudinally extending bore 31.

Movement of the main valve 14 to the .open position to drive a fastener and to the closed position to allow the driving piston to be returned to drive a subsequent fastener is controlled by a pilot valve 33 that is operated by a trigger 34 that is pivotally connected to the housing at the juncture between the handle and the cylinder 7 by a pivot pin 35. The function .of the pilot valve is to vent chamber 28 to allow the compressed air in reservoir 4 acting on the unbalanced area on the upper side .of piston 25 to move the main valve down and away from gasket opening 16 and admit high-pressure air to chamber 10. In the embodiment shown, the pilot valve consists of a ball member 37 which is resiliently biased against valve seat 38 by spring 36 located in bore 31 to prevent the escape of air from chamber 28. Located between the trigger 34 and ball 37 is a valve pin 39 which rests on the bottom wall of U-shaped trigger 34 out of engagement with the ball 37. When the trigger 34 is moved counterclockwise, the valve pin 39 is moved upwardly to move ball 37 away from seat 38 to vent chamber 28 through vent passages 40 formed in pin 39.

When the T311 37 is moved away from seat 38 ,to vent chamber 28, main valve 14 opens and, during its down- Ward movement, the piston 25 seats against the ball valve 37 to prevent the escape of high-pressure air from reservoir 4 through port 30, bore 31, and chamber 28. To accommodate the ball valve 37, the piston portion 25 defines a valve seat 43 on its under-side.

When the main valve 14 is moved downwardly to open opening 16, the reservoir 4 and chamber are interconnected to direct compressed air against the upper surface of piston 8 to move it and driver 9 with a sharp, quick driving action against a fastener located in nose assembly 11. When the trigger is released, ball 37 is returned to seat 38 by spring 36 and compressed air introduced into chamber 28 through port 30 and bore 31 acts on the underside of piston 25 to seat valve head against gasket 17 and close off the flow of air into cylinder 7.

When valve 14 closes, it is necessary to vent the air in chamber 10 in order to allow the piston 8 to be moved from the driven to the driving positions. To this end, there is provided an exhaust valve assembly 45 which functions to vent cylinder chamber 10 and chamber 21 in cap 19 to atmosphere when the main valve is moved to the closed position. The reduction of pressure on the top of piston 8 permits the application of a relatively small force acting in the opposite direction on piston 8 to return it to the driving position. The exhaust valve includes a stem 46 that extends upwardly from the valve head 15 and a hat-shaped rubber valve seat and seal 47 that is located in an opening 50 in the cap 19. The outwardly extending flange 47a of seal 47 has an outside diameter slightly greater than the inner diameter of recess 50a of opening 50. Thus, when the seal is inserted, the lower portion of the seal is biased inwardly to increase the sealing action between land 48 and seal 47 when land 48 is moved downwardly. The stem 46 includes an outwardly extending land 48 having an outer diameter equal to the inner diameter of the valve seat member 47. Extending through one wall of the valve seat 47 is an outlet port 49, the opening and closing of which is controlled by land 48. As shown in FIG- URE 1, when the main valve 14 is closed, the land 48 is located above port 49 and thus the air under pressure in chambers 10 and 21 is vented to atmosphere through port 49. When the main valve is open, the stem 46 and land 48 are moved downwardly to the position shown in FIGURE 2, wherein the outlet port 49 is sealed off from chamber 10 and 21 and air cannot escape through exhaust port 49. The elastic composition of the valve seat and seal makes for a highly efiicient sea-ling arrangement which aids in obtaining economical use of the high-pressure air supplied to the tool.

The particular tool shown includes an arrangement whereby the driving piston 8 is moved from the driven to driving positions by compressed air from reservoir 4 to chamber 51 formed between piston lands 8a, 8b. The piston land 8a is larger than piston land 8b, with the result that the air under pressure introduced to chamber 51 drives piston 8 upwardly toreturn the piston to the driving position after the main valve 14 is closed and chambers 10, 21 are vented to atmosphere through exhaust valve 45. Chamber 51 is in communication with reservoir 4 through opening 52 in the wall of cylinder 7.

While the details of the driving piston 8, driver blade 9, nose assembly 11, and magazine 13 are not important to an understanding of the present invention, it is to be noted that the driver blade 9 is secured to the piston 8 by a plurality of blade pins 54 that extend through a blade insert 55 located in a recess 56 formed in the piston 8. The blade insert 55 is secured in place relative to the piston by a threaded plug 57. To reduce the shock loads on the piston when it is driven, a bumper 60 fitted into a recess 61 formed on the underside. of the piston 8 and extending .therebelow is provided.

The nose assembly 11 through which the driver blade moves includes a pair of guide plates 62, 63, which define therebetween a guideway 64 for the fastener to be driven by the blade 9.

The magazine 13, secured to the opposite ends of the tool housing 2, includes a suitable support for the fasteners and a follower assembly 65 for biasing the fasteners into position to be driven. The magazine could obviously take many different configurations.

As can be-seen from the drawings, the valve assemblage including the main, pilot and exhaust valve is located in substantial alignment and generally parallel to cylinder 7 and driving piston 8. It can be appreciated that if replacement of any of these parts is desired, or the driver blade or piston must be removed, it can be readily accomplished by merely removing the cap 19, which exposes these various components for ready handling. This unique construction of the valve assemblage and its relationship with the driving piston makes for a compact, highly efficient, readily accessible tool.

The operation of the tool shown in the drawings is as follows:

Prior to the time a fastener is driven, high-pressure air admitted to reservoir 4 through hose 5 acts on the undersurface of valve head 15 and the upper and lower surfaces of piston portion 25 to maintain the main control valve closed against gasket 17 and exhaust valve 45 open to vent the air above piston 8 in chambers 10 and 21 to atmosphere through exhaust port 49. The pilot valve 33 is maintained closed against seat 38 by spring 36 and air pressure admitted to chamber 28 through port 30 and bore 31. Prior to firing, piston 8 is biased and held against gasket 17 by the air under pressure introduced into chamber 51 from reservoir 4 through opening 52.

When a fastener is to be driven, the trigger 34 is moved counterclockwise by the operator to move pin 39 against ball 37 to move it away from seat 38 thereby venting chamber 28 to atmosphere through vent passages 40. The unbalanced force acting on the upper side of piston 25 moves valve 14 downwardly to move valve head 15 away from gasket 17 and interconnect chambers 10 and 21 with reservoir 4 to allow high-pressure air to act on the upper surface of piston 8 to drive same. When valve 14 moves downwardly, the land 48 on valve stem 46 blocks off outlet port 49 from chamber 21 to prevent the escape of high-pressure air.

The downward movement of valve 14 brings piston seat 43 into engagement with ball 37, thus preventing the escape of high-pressure air through pilot valve 33.

After a fastener is driven, the trigger is released and ball 37 returns to seat 38. High-pressure air then flows through port 30 and bore 31 into chamber 28 to act on the underside of piston 25 to return valve 14 to the closed position. When valve 14 is closed, land 48 is located above outlet port 49 and the air in chambers 20 and 21 is vented out through outlet port 49. With the reduction of air pressure on top of piston 8, the high-pressure air acting on the unbalanced portion of land 8a moves piston 8 back to a driving position against the underside of gasket 17.

From the foregoing, it will be observed that numerous variations and modifications may be effected without departing from the true spirit and scope of the novel con cepts of the invention. For example, a spring can be used for returning the piston after it has been driven in place of the air return system herein disclosed. Also, the pilot valve need not necessarily be in direct alignment with the main valve so long as it controls the operation of the main valve and in so doing prevents the leakage of high-pressure air when the tool is being fired.

It is, of course, intended to cover by the appended claims all such modifications and embodiments that fall within the true spirit and scope of the invention.

We claim: i g

1. A fastener driving tool having a housing with a cylinder at one end thereof and defining a reservoir having an opening adjacent said cylinder and adapted to receive fluid under high pressure, a driving piston slidably disposed in said cylinder, a driver blade secured to one side of said piston, a removable cap member secured to said housing and defining a chamber interconnecting said opening in the reservoir with the cylinder space above the piston, main valve means located below said cap and disposed immediately adjacent said cylinder and extending parallel thereto for controlling the flow of highpressure fluid between the reservoir and said chamber, pilot valve means controlling the operation of said main valve and exhaust valve means for venting the air from said chamber and adjacent cylinder space when the main valve means is closed, the main, pilot and exhaust valve means being in alignment whereby components thereof can be readily withdrawn from the housing when the cap is removed.

2. A fastener driving tool having a housing with a cylinder disposed at one end thereof and defining a reservoir adapted to receive fluid under high pressure and having an opening immediately adjacent said cylinder, a driving piston slidably disposed in said cylinder, a fastener driving member secured to one side of said piston, a removable cap member secured to said housing and defining a chamber interconnecting said opening in the reservoir and the space in the cylinder above the piston, a valve assembly for controlling the flow of high pressure fluid from the reservoir through said opening to said cylinder including aligned main, pilot and exhaust valve means disposed be neath said cap, whereby they can be readily withdrawn when the cap is removed from the housing, said main valve means being disposed immediately adjacent said cylinder and extending parallel thereto, said exhaust valve means which functions to vent air from said chamber and cylinder space including a valve stem connected to said main valve and a cooperating valve seat and seal member located in said cap member.

3. A fastener driving tool having a housing with a cylinder disposed at one end thereof and defining a reservoir adapted to receive compressed air and having an opening immediately adjacent said cylinder, a driving piston slidably disposed in said cylinder, a driver blade secured to one side of said piston, a removable cap member secured to said housing and defining a vent port and a chamber interconnecting the opening in said reservoir and the other side of said piston, a valve assemblage for controlling the flow of compressed air from the reservoir to said cylinder through said opening including aligned main, pilot and exhaust valve means disposed beneath said cap and parallel to said cylinder, said main valve means including a valve head, a valve stem, a piston portion slidably disposed in a recess defined by said housing within said reservoir, and passage means intercommunicating said reservoir with the chamber located on the opposite side of said piston portion for maintaining the main valve closed, the exhaust valve means for venting the air from said cap chamber including a valve stem connected to said main valve and a cooperating elastic valve seat and seal member located in said cap member, said valve seat and seal member defining an exhaust port communicating with said cap vent port and said valve stem including a land portion adapted to control the flow of air through said exhaust port.

4-. A fastener driving tool as set forth in claim 3 in which the cooperating elastic valve seat and seal member comprises a resilient hat-shaped member having an outlet port disposed in an opening defined by the cap member, said land portion cooperating with said elastic member to control the fiow of air between said chamber and the port defined by said elastic member.

References Cited by the Examiner UNITED STATES PATENTS 3,051,135 2/1962 Smith 91417 X 3,084,672 4/1963 Dalton 91-417 3,106,136 10/1963 Langas 91417 3,152,519 10/1964 Doyle 91-417 X 3,173,340 3/1965 Doyle 91--461 MARTIN P. SCHWADRON, Primary Examiner.

SAMUEL LEVINE, Examiner.

P. T. COBRIN, Assistant Examiner. 

3. A FASTENER DRIVING TOOL HAVING A HOUSING WITH A CYLINDER DISPOSED AT ONE END THEREOF AND DEFINING A RESERVOIR ADAPTED TO RECEIVE COMPRESSED AIR AND HAVING AN OPENING IMMEDIATELY ADJACENT SAID CYLINDER, A DRIVING PISTON SLIDABLY DISPOSED IN SAID CYLINDER, A DRIVER BLADE SECURED TO ONE SIDE OF SAID PISTON, A REMOVABLY CAP MEMBER SECURED TO SAID HOUSING AND DEFINING A VENT PORT AND CHAMBER INTERCONNECTING THE OPENING IN SAID RESERVOIR AND THE OTHER SIDE OF SAID PISTON, A VALVE ASSEMBLAGE FOR CONTROLLING THE FLOW OF COMPRESSED AIR FROM THE RESERVOIR TO SAID CYLINDER THROUGH SAID OPENING INCLUDING ALIGNED MAIN, PILOT AND EXHAUST VALVE MEANS DISPOSED BENEATH SAID CAP AND PARALLEL TO SAID CYLINDER, SAID MAIN VALVE MEANS INCLUDING A VALVE HEAD, A VALVE STEM, A PISTON PORTION SLIDABLY DISPOSED IN A RECESS DEFINED BY SAID HOUSING WITHIN SAID RESERVOIR, AND PASSAGE MEANS INTERCOMMUNICATING SAID RESERVOIR WITH THE CHAMBER LOCATED ON THE OPPOSITE SIDE OF SAID PISTON PORTION FOR MAINTAINING THE MAIN VALVE CLOSED, THE EXHAUST VALVE MEANS FOR VENTING THE AIR FROM SAID CLAP CHAMBER INCLUDING A VALVE STEM CONNECTED TO SAID MAIN VALVE AND A COOPERATING ELASTIC VALVE SEAT AND SEAL MEMBER LOCATED IN SAID CAP MEMBER, SAID VALVE SEAT AND SEAL MEMBER DEFINING AN EXHAUST PORT COMMUNICATING WITH SAID CAP VENT PORT AND SAID VALVE STEM INCLUDING A LAND EXHAUST PORT. 